CN110391644B

CN110391644B - Battery protection system, battery pack and protection method

Info

Publication number: CN110391644B
Application number: CN201910293716.8A
Authority: CN
Inventors: 栗国星
Original assignee: O2micro Electronics Wuhan Co ltd
Current assignee: O2micro Electronics Wuhan Co ltd
Priority date: 2018-04-19
Filing date: 2019-04-12
Publication date: 2022-04-26
Anticipated expiration: 2039-04-12
Also published as: JP7225011B2; GB201806415D0; GB2563489B; JP2019198216A; EP3557717B1; GB2563489A8; EP3557717A1; US20190326746A1; ES2849624T3; CN110391644A; GB2563489A; US10978867B2

Abstract

Disclosed are a battery protection system, a battery pack, and a protection method. The protection system includes a plurality of protection modules, each module including: a plurality of monitoring terminals for monitoring the states of the plurality of battery units; an output terminal for outputting the protection signal; a switching terminal for receiving a switching signal; and a detection module which switches from the normal operation mode to the rapid test mode in response to the switching signal, generates the protection signal after a delay time when an abnormal condition of the battery cell is detected, sets the delay time to a first time interval if the abnormal condition is detected in the normal operation mode, and sets the delay time to a second time interval less than the first time interval if the abnormal condition is detected in the rapid test mode. In addition, the plurality of protection modules comprise a first protection module and a second protection module, and the switching end and the first monitoring end of the first protection module receive signals from the output end of the second protection module. The protection system can provide protection for the battery more quickly.

Description

Battery protection system, battery pack and protection method

Technical Field

The invention relates to the field of batteries, in particular to a battery protection system, a battery pack and a protection method.

Background

Fig. 1 is a circuit diagram of a battery protection system 100 in the prior art. As shown in fig. 1, the battery protection system 100 includes a first level protection module 108 and a second level protection module 102. The first stage protection module 108 protects the battery pack 104 from over/under voltage, over current, short circuit, and over/under temperature damage. In the event that the first level protection module 108 is inoperative (e.g., fails), the second level protection module 102 provides backup protection, such as: battery pack 104 is protected from abnormal conditions such as overvoltage. For example, when a charger (not shown in the figure) charges the battery PACK 104 through the ports PACK + and PACK-, if the secondary protection module 102 detects that an abnormal condition exists in the battery PACK 104, the protection module 102 generates a protection signal 110 to turn on the switch MN1 to blow the fuse 106, so that the battery PACK 104 is disconnected from the charger. Further, to avoid false detection, when the protection module 102 detects evidence of an abnormal condition in the battery pack 104, the protection module 102 delays the output of the protection signal 110 for a preset time interval Δ T1 (e.g., 1, 2, or 4 seconds, etc.). If the protection module 102 detects the abnormal state for the preset time interval Δ T1, the protection module 102 determines that an abnormal condition has occurred in the battery pack 104.

The protection system 100 of fig. 1 is used to protect a battery pack having a small number (e.g., five) of cells. In applications with a greater number of battery cells, the battery protection system includes two or more protection modules 102.

Fig. 2A is a circuit diagram of a battery protection system 200A in the prior art. As shown in fig. 2A, the battery protection system 200A includes a protection module 202 and a protection module 212. The protection module 202 (hereinafter referred to as a low-side module) monitors the battery pack 204 and the protection module 212 (hereinafter referred to as a high-side module) monitors the battery pack 214. If a sign of an anomaly is detected in the battery pack 204, the low side module 202 begins timing. After a preset time interval Δ T1 (e.g., 1, 2, or 4 seconds, etc.), if the low side module 202 confirms that an abnormal condition does exist in the battery pack 204, the low side module 202 outputs a protection signal 210 to blow the fuse 206. Similarly, if an abnormal condition is detected in another group of battery cells 214, the high side module 212 outputs a protection signal 216 after a preset time interval Δ T1. As shown in fig. 2A, the low side module 202 receives a protection signal 216 from the high side module 212 at its monitor terminal BAT5 and generates a protection signal 210 to blow the fuse 206 in response to the protection signal 216. Thus, the battery protection system 200A may protect both sets of

battery cells

204 and 214 from abnormal conditions.

However, when the low side module 202 receives the protection signal 216 from the high side module 212, the low side module 202 further delays the output of the protection signal 210 by the preset time interval Δ T1. Therefore, from the detection of the sign of abnormality in the battery pack 214 to the output of the protection signal 210, the delay time Δ T2 thereof is about twice the preset time interval Δ T1(Δ T2 — 2 × Δ T1). Such a time delay Δ T2 is too long such that the protection system 200A may not be able to protect the battery pack 214 in a timely manner.

Fig. 2B is a circuit diagram of another battery protection system 200B in the prior art. Battery protection system 200B is similar to battery protection system 200A described above, except that in battery protection system 200B, protection signal 216 from high-side module 212 is output to control switch MN2, rather than to low-side module 202. Therefore, if an abnormal condition is detected in the battery pack 214, the high side module 212 outputs a protection signal 216 to turn on the switch MN2 to blow the fuse 206. The delay time of the high side module 212 from the detection of the sign of abnormality to the output of the protection signal 216 is a preset time interval Δ T1. Further, the battery protection system 200B includes resistors R1, R2, R4, R5, R6, and switches MN1 and MP1, which constitute a level shifter. If an abnormal condition is detected in the battery pack 204, the low side module 202 outputs a protection signal 210. The level shifter shifts the voltage level of the protection signal 210 to a higher voltage level to turn on the switch MN2 to blow the fuse 206. More specifically, the protection signal 210 first turns on the switch MN1 to pull down the gate voltage of the switch MP1 (e.g., PMOS transistor). Therefore, the switch MP1 turns on the gate voltage of the pull-up switch MN2 (e.g., NMOS transistor). Accordingly, the switch MN2 turns on to blow the fuse 206. The delay time from the detection of the indication of abnormality in the battery pack 204 to the output of the protection signal 210 by the low side module 202 is also the predetermined time interval Δ T1. Therefore, the battery protection system 200B in fig. 2B may provide better protection for the battery packs 204 and 214 than the battery protection system 200A in fig. 2A.

However, the above-described level shifter includes the resistors R1, R2, R4, R5, and R6 and the switches MN1 and MP1, thereby increasing the printed circuit board size of the protection system 200B and the power consumption thereof.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a battery protection system, a battery pack and a protection method, which are used for protecting a battery more quickly when the abnormal condition of the battery is detected.

In order to solve the technical problem, the invention provides a battery protection system which comprises a plurality of protection modules. Each protection module includes: the monitoring terminals are used for monitoring the states of the battery units; an output terminal for outputting a protection signal; the switching terminal is used for receiving a switching signal; and a detection module connected to the plurality of monitoring terminals, the output terminal, and the switching terminal, and configured to switch from a normal operation mode to a fast test mode in response to the switching signal, and to generate the protection signal after a delay time when an abnormal condition is detected in the plurality of battery cells, wherein the detection module sets the delay time to a first time interval if the abnormal condition is detected in the normal operation mode, and sets the delay time to a second time interval less than the first time interval if the abnormal condition is detected in the fast test mode. In addition, the plurality of protection modules comprise a first protection module and a second protection module, and the switching end and the first monitoring end of the first protection module are connected with the second protection module and used for receiving signals from the output end of the second protection module.

The present invention also provides a battery pack, including: a first group of battery cells; a second group of battery cells connected to the first group of battery cells; a first protection module connected to the first group of battery cells; and a second protection module connected with the second group of battery cells. Each of the first and second protection modules comprises: the monitoring terminals are used for monitoring the states of a corresponding group of battery units in the first group of battery units and the second group of battery units; an output terminal for outputting a protection signal; the switching terminal is used for receiving a switching signal; and a detection module connected to the plurality of monitoring terminals, the output terminal, and the switching terminal, and configured to switch from a normal operation mode to a rapid test mode in response to the switching signal, and to generate the protection signal after a delay time when an abnormal condition is detected in the corresponding group of battery cells, wherein the detection module sets the delay time of the protection signal to a first time interval if the abnormal condition is detected in the normal operation mode, and sets the delay time of the protection signal to a second time interval less than the first time interval if the abnormal condition is detected in the rapid test mode. In addition, the switching end and the first monitoring end of the first protection module are connected with the second protection module and used for receiving signals from the output end of the second protection module.

The present invention also provides a protection method of protecting a battery pack including at least a first group of battery cells and a second group of battery cells, the protection method including: monitoring the state of the first group of battery units through a plurality of monitoring ends of a first protection module; if the abnormal condition is detected in the first group of battery units, outputting a first protection signal through a first output end of the first protection module after delay time; receiving a switching signal at a switching end of the first protection module; controlling the first protection module to switch from a normal working mode to a fast testing mode in response to the switching signal; setting the delay time of the first protection signal to a first time interval if the abnormal condition is detected in the normal operation mode; setting the delay time of the first protection signal to a second time interval less than the first time interval if the abnormal condition is detected in the fast test mode; monitoring, by a second protection module, a state of the second group of battery cells; and outputting a second protection signal through a second output terminal of the second protection module if an abnormal condition is detected in the second group of battery cells. In the protection method, the switching terminal of the first protection module and the first monitoring terminal of the first protection module receive the second protection signal from the second output terminal of the second protection module.

When the battery protection system, the battery pack and the protection method provided by the invention detect that the second group of battery units have abnormal conditions, the first protection module is informed of the abnormal conditions, and the first protection module is controlled to enter a rapid test mode. Accordingly, a delay time from the detection of the abnormal condition to the execution of the battery protection action is shortened, thereby providing more reliable protection for the battery.

Drawings

Further objects, specific structural features and advantages of the present invention will be understood from the following description of some embodiments of the invention, taken in conjunction with the accompanying drawings.

Fig. 1 is a circuit diagram of a battery protection system in the prior art.

Fig. 2A is a circuit diagram of a battery protection system in the prior art.

Fig. 2B is a circuit diagram of a battery protection system in the prior art.

Fig. 3 is a circuit diagram of a battery protection system according to an embodiment of the present invention.

FIG. 4 is a circuit schematic of a detection module according to one embodiment of the invention.

Fig. 5 is a flow chart illustrating a battery protection method according to an embodiment of the invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention. While the invention is illustrated and described in connection with these embodiments, it is to be understood that the invention is not limited to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present invention. It will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.

Embodiments of the present invention provide a battery protection system including a plurality of protection modules for protecting a plurality of groups of battery cells. These protection modules can selectively enter a normal operating mode or a fast test mode. If an abnormal condition is detected in the battery pack in the normal operation mode, the protection module may output a protection signal after a first time interval Δ TN (e.g., 1 second, 2 seconds, 4 seconds, etc.); if an abnormal condition is detected in the battery pack in the fast test mode, the protection module may output the protection signal after a second time interval Δ TF that is much smaller than the first time interval Δ TN. The plurality of protection modules includes at least a first protection module and a second protection module. The first protection module may generate a first protection signal to protect the first group of battery cells. The first protection module may also receive a second protection signal generated by the second protection module to generate a first protection signal to protect the second group of battery cells. In addition, the second protection signal may control the first protection module to enter a fast test mode. Therefore, the delay time from the detection of the indication of abnormality in the second group of battery cells to the output of the first protection signal is approximately equal to the sum of the first time interval and the second time interval (e.g., Δ TN + Δ TF). In one embodiment, because the second time interval Δ TF is relatively short (e.g., 16 milliseconds, 32 milliseconds, etc.), the time delay Δ TN + Δ TF is substantially shorter than the time delay Δ T2 mentioned in the prior art battery protection system 200A. Furthermore, the embodiment of the present invention omits the level shifter mentioned in the related art battery protection system 200B, thereby reducing the printed circuit board size of the system and the power consumption of the system.

Fig. 3 is a schematic circuit diagram illustrating a battery protection system in a battery pack 300 according to an embodiment of the present invention. As shown in fig. 3, the battery pack 300 includes a first group of battery cells 304 and a second group of battery cells 314. The battery protection system includes a first level protection circuit 308, a second level protection circuit (including a second level protection module 302 and a second level protection module 312), and a fuse 306 (which may also be referred to as a fuse). The first stage protection circuit 308 may protect the battery packs 304 and 314 from abnormal conditions such as over-voltage, under-voltage, over-current, short circuit, over-temperature, and/or under-temperature. The

secondary protection modules

302 and 312 may provide backup protection for the battery packs 304 and 314 if the primary protection circuit 308 is inoperative or otherwise fails (e.g., by blowing the fuse 306).

In one embodiment, the

protection modules

302 and 312 have similar circuit structures and functions. For example, each of the

protection modules

302 and 312 includes a set of monitor terminals (e.g., ports labeled "BAT 1" and "BAT 2". multidot.. times. "BAT 5"), output terminals (e.g., ports labeled "OV"), and switch terminals (e.g., ports labeled "VCC"). The monitoring terminal is used for monitoring the state of the

corresponding battery pack

304 or 314. The output terminal OV is used for outputting a protection signal (e.g., S) when an abnormal condition (e.g., an overvoltage condition) is detected in the battery pack_OV1Or S_OV2). The handover terminal VCC is configured to receive a handover signal. The switching terminal VCC may also serve as a power input terminal for receiving power so that the protection module may operate. In addition, the

protection modules

302 and 312 also include a detection module connected to the plurality of ports. The detection module may determine whether an abnormal condition (e.g., an overvoltage condition) exists in the battery pack based on the information received at the monitoring terminal. If an abnormal condition is detected, the detection module generates a protection signal after a predetermined time delay. The detection module can be switched from a normal working mode to a rapid test mode under the control of the switching signal.

More specifically, in one embodiment, to avoid false detection, when the

protection module

302 or 312 detects a sign of abnormality in the battery pack, the protection module does not immediately output a protection signal, but waits for a preset time interval Δ TN (e.g., 1 second, 2 seconds, 4 seconds, etc.). After the time interval Δ TN has elapsed, if the protection module still detects the sign of the abnormality, the protection module determines that an abnormal condition is indeed present in the battery pack and generates a protection signal. In one embodiment, when a protection module (e.g., 302 or 312) is manufactured and packaged as a finished Integrated Circuit (IC), the protection module undergoes a series of tests to ensure that the protection module is functioning properly, and these tests are performed in a fast test mode. In the fast test mode, the time delay Δ TF for outputting the protection signal is relatively short (e.g., 16 ms, 32 ms, etc.). In one embodiment, the voltage signal at the switching terminal VCC (hereinafter, referred to as a switching signal) may control the protection module to enter a normal operation mode or a fast test mode. For example, if the voltage level of the switching signal is within the normal operating voltage range of the protection module (in other words, the protection module receives the supply voltage within the normal operating range), the protection module operates in the normal operating mode. In the normal operation mode, if the battery pack is detected to have an abnormal condition, the detection module sets the delay time of the protection signal to a first time interval Δ TN (e.g., 1 second, 2 seconds, 4 seconds, etc.). If the voltage of the switching signal is higher than a preset voltage level (e.g., higher than VBAT5+5V), the protection module enters a fast test mode. Where "VBAT 5" represents the voltage level at monitor terminal BAT 5. In the fast test mode, the detection module sets the output delay of the protection signal to a second time interval Δ TF (e.g., 16 milliseconds, 32 milliseconds, etc.) if an abnormal condition of the battery pack is detected. The second time interval Δ TF is smaller than the first time interval Δ TN.

In the example of FIG. 3, the protection module 302 (also referred to as a first protection module) monitors the state of the first group of cells 304 via its monitor terminals BAT1-BAT3, and the protection module 312 (also referred to as a second protection module) monitors the state of the second group of cells 314 via its monitor terminals BAT1-BAT 4. The switch terminal VCC and the first monitor terminal BAT5 of the first protection module 302 are connected to the second protection module 312 and receive signals from the output terminal OV of the second protection module 312. In the example of fig. 3, the first monitor terminal BAT5 of the first protection module 302 is via a resistor R_FTIs connected to the second protection module 312 and via a resistor R_FTA signal is received from the output OV of the second protection module 312. If an abnormal condition is detected in the first group of battery cells 304, the first protection module 302 delays a first time interval Δ TN (e.g., 1 second, 2 seconds, 4 seconds, etc.) and then provides a signal at its outputOV outputs a first protection signal S_OV1. First guard signal S_OV1The circuit 310 (e.g., which may specifically include a switch connected between the fuse 306 and ground) may be controlled to blow the fuse 306. If an abnormal condition is detected in the second group of battery cells 314, the second protection module 312 outputs a second protection signal S to the first monitor terminal BAT5 of the first protection module 302 after delaying the first time interval Δ TN_OV2. In response to the second protection signal S_OV2The first protection module 302 also outputs a first protection signal S at its output OV_OV1To blow the fuse 306. Therefore, the battery protection system according to the embodiment of the present invention protects a plurality of sets of battery cells using a plurality of protection modules. In addition, the switch terminal VCC of the first protection module 302 also receives the second protection signal S from the output terminal OV of the second protection module 312_OV2. In response to a second protection signal S received on the switch terminal VCC_OV2The detection module of the first protection module 302 switches from the normal operation mode to the fast test mode. In the fast test mode, a protection signal S is output_OV1Is set to a second time interval deltatf (e.g., 16 milliseconds or 32 milliseconds, etc.) that is much smaller than the first time interval deltatn (1 second, 2 seconds, 4 seconds, etc.). Therefore, the first protection signal S is outputted from the detection of the abnormal state in the second group battery cell 314 to the output of the first protection signal S_OV1Is approximately Δ TN + Δ TF, and is much shorter than the delay time Δ T2 (e.g., Δ T2 ═ 2 × Δ T1) mentioned in the prior art battery protection system 200A.

Fig. 4 is a circuit schematic of the detection module 402 in the first protection module 302 according to an embodiment of the present invention. The second protection module 312 may have a similar circuit structure. Fig. 4 is described below in conjunction with fig. 3. As shown in FIG. 4, the detection module 402 includes a monitor circuit 418 connected to monitor terminals BAT1-BAT5, a delay circuit 428 connected to the monitor circuit 418, and a fast test mode detection circuit 432 (abbreviated as: fast test detection circuit 432) connected to the delay circuit 428.

In one embodiment, monitoring circuit 418 monitors the cell voltage status of a group of battery cells, and as suchIf it is detected that the cell voltage is greater than the reference voltage V_REF*(R_D1+R_D2)/R_D1Then an indication signal 430 is generated. For example, the monitoring circuit 418 may include a set of comparators 422_ 1-422 _ 5. Each comparator compares the corresponding voltage signal V1, V2, V3, V4 or V5 with a reference voltage V_REFBy comparison, the voltage signals V1, V2, V3, V4 or V5 indicate the voltage difference V between the monitor terminal VSS and the adjacent two terminals BAT1-BAT5_DIS. If the corresponding voltage signal V1, V2, V3, V4 or V5 is greater than the reference voltage V_REF(e.g., corresponding voltage difference V)_DISGreater than a reference voltage V_REF*(R_D1+R_D2)/R_D1) Then the comparator outputs a corresponding signal OV1, OV2, OV3, OV4 or OV5 to or gate 424, thereby causing or gate 424 to output indication signal 430. In the first protection module 302 illustrated in fig. 3, a voltage difference between the ports VSS and BAT1, a voltage difference between the ports BAT1 and BAT2, and a voltage difference between the ports BAT2 and BAT3 respectively represent voltages of the respective battery cells in the first group of battery cells 304. In addition, since the voltage signal at the first monitor terminal BAT5 is controlled according to the cell voltage status of the second group of battery cells 314, the voltage difference between the ports BAT4 and BAT5 indicates the voltage status of the second group of battery cells 314. Thus, the cell voltages monitored by the monitoring circuit 418 include the cell voltages of the first set of cells 304 and the cell voltages of the second set of cells 314.

As described above, in one embodiment, the voltage signal at the first monitor terminal BAT5 of the first protection module 302 is controlled based on the cell voltage status of the second group of battery cells 314. More specifically, as illustrated in FIG. 3, the output OV of the second protection module 312 (hereinafter referred to as the second output OV) is connected via a resistor R_FTAnd R_OVIs connected to the first group of battery cells 304, and the first monitor terminal BAT5 and the resistor R of the first protection module 302_FTAnd R_OVThe connection nodes of (1) are connected. Thus, the resistor R_OVThe voltage drop across the terminals (e.g. representing the voltage difference between the ports BAT5 and BAT4 of the first protection module 302) is controlled by the voltage at the second output terminal OV. At one endIn one embodiment, the second protection signal S at the second output OV_OV2May be high enough that the resistor R_OVThe voltage drop between the two ends is greater than the reference voltage V_REF*(R_D1+R_D2)/R_D1. Therefore, if an abnormal condition occurs in the second group of battery cells 314, the first protection module 302 may detect the abnormal condition of the second group of battery cells 314 through the first monitoring terminal BAT5 thereof.

Returning to fig. 4, in one embodiment, delay circuit 428 begins timing in response to indicator signal 430 and generates first guard signal 434 after a predetermined time delay Δ T. In one embodiment, delay circuit 428 includes a timer 426. Timer 426 may include any circuit capable of timing. For example, timer 426 may include a capacitor controlled by a preset current. In response to the indication signal 430, the preset current starts to charge (or discharge) the capacitor, so that the voltage of the capacitor changes. When the voltage change of the capacitor reaches a prescribed amount, the timer 426 generates a signal to the buffer so that the buffer outputs a protection signal 434. Thus, the time delay Δ T may be controlled by controlling the preset current and/or the prescribed amount of the capacitor voltage. For example, the time delay Δ T may be shortened by increasing the preset current or by decreasing the prescribed amount.

In one embodiment, if the fast detection circuit 432 receives the second protection signal S from the output OV of the second protection module 312 at the switch terminal VCC_OV2Then the fast detection circuit 432 controls the delay circuit 428 to switch the predetermined time delay deltat from the first time interval deltatn to the second time interval deltatf. For example, the fast detection circuit 432 includes a comparator 432. The comparator 432 can compare the voltage difference between the switching terminal VCC and the first monitoring terminal BAT5 with a threshold voltage V_THA comparison is made and a result signal TEST _ MD is generated to control the delay circuit 428 according to the comparison. In one embodiment, the second protection signal S_OV2Is sufficiently high to cause the resistor R to be connected to_FTThe voltage drop across the terminals (e.g., representing the voltage difference between the ports VCC and BAT 5) is greater than the threshold voltage V_TH。

Thus, in the example of FIG. 4, if an abnormal condition (e.g., an overvoltage condition) is detected in the first group of battery cells 304 via the ports VSS, BAT1, BAT2, and BAT3, the delay circuit 428 delays the first time interval Δ TN before outputting the protection signal 434 to protect the first group of battery cells 304. If an abnormal condition (e.g., an overvoltage condition) is detected in the second group of battery cells 314 via ports BAT4 and BAT5, the delay circuit 428 delays the second time interval Δ TF before outputting the protection signal 434 to protect the second group of battery cells 314. The delay time from when the second protection module 312 detects a sign of abnormality in the second group of battery cells 314 to when the first protection module 302 outputs the protection signal 434 is approximately equal to Δ TN + Δ TF.

Fig. 5 is a flow chart illustrating a battery protection method according to an embodiment of the invention. Fig. 5 is described below in conjunction with fig. 3 and 4. Those skilled in the art will appreciate that the specific steps covered by fig. 5 are merely exemplary. That is, the present invention is applicable to other reasonable flows or steps that improve upon fig. 5.

At step 502, the first protection module 302 monitors the status of the first group of cells 304 via a plurality of monitoring terminals. For example: the first protection module 302 monitors the cell voltages of the battery pack 304 and determines whether the cell voltages are greater than a reference voltage. If any of the cell voltages are greater than the reference voltage, the first protection module 302 begins timing. When the predetermined time interval expires, the first protection module 302 determines that an abnormal condition (e.g., an overvoltage condition) is indeed present in the battery pack 304 if the cell voltage is still greater than the reference voltage.

In step 504, if an abnormal condition (e.g., an overvoltage condition) is detected in the battery pack 304, the first protection module 302 outputs a first protection signal S through its first output OV after a delay time_OV1。

In step 506, the first protection module 302 receives a handover signal (e.g., S) at its handover terminal VCC_OV2)。

In step 508, the first protection module 302 responds to the switching signal (e.g., S)_OV2) From normal operationThe mode switches to the fast test mode.

In step 510, if the abnormal condition is detected in the normal operation mode, the first protection module 302 will apply a first protection signal S_OV1Is set to the first time interval Δ TN (e.g., one second, two seconds, four seconds, etc.).

In step 512, if the abnormal condition is detected in the fast test mode, the first protection module 302 will apply a first protection signal S_OV1Is set to a second time interval Δ TF (e.g., sixteen or thirty-two milliseconds, etc.) that is less than the first time interval Δ TN.

In step 514, the second protection module 312 monitors the status of the second set of battery cells 314. For example, the second protection module 312 monitors the battery pack 314 and determines whether any of the cell voltages are greater than a reference voltage. If any of the cell voltages are greater than the reference voltage, the second protection module 312 begins timing. When the predetermined time interval expires, the second protection module 312 determines that an abnormal condition (e.g., an overvoltage condition) is indeed present in the battery pack 314 if the cell voltage is still greater than the reference voltage.

In step 516, if an abnormal condition (e.g., an overvoltage condition) is detected in the battery pack 314, the second protection module 312 outputs a second protection signal S via a second output OV thereof_OV2。

At step 518, the first protection module 302 receives at its switch VCC a signal (e.g., S) from the second output OV of the second protection module 312_OV2)。

The first protection module 302 also receives a signal (e.g., S) from the second output OV of the second protection module 312 at its first monitor terminal BAT5 at step 520_OV2)。

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described (or portions thereof), and it is recognized that various modifications are possible within the scope of the claims. Other modifications, variations, and alternatives are also possible. Accordingly, the claims are intended to cover all such equivalents.

Claims

1. A battery protection system, comprising:

a plurality of protection modules, wherein each protection module comprises:

the monitoring terminals are used for monitoring the states of the battery units;

an output terminal for outputting a protection signal in case an abnormal condition is detected in the plurality of battery cells;

the switching terminal is used for receiving a switching signal; and

a detection module connected to the plurality of monitoring terminals, the output terminal, and the switch terminal, and configured to: switching from a normal operation mode to a fast test mode in response to the switching signal, and generating the protection signal after a delay time when an abnormal condition is detected in the plurality of battery cells, wherein the detection module sets the delay time to a first time interval if the abnormal condition is detected in the normal operation mode, sets the delay time to a second time interval less than the first time interval if the abnormal condition is detected in the fast test mode,

wherein the plurality of protection modules comprise: a first protection module generating a first protection signal for protecting the first group of battery cells; and a second protection module generating a second protection signal for protecting a second group of battery cells, the switching terminal and the first monitoring terminal of the first protection module being connected to the second protection module for receiving a signal from the output terminal of the second protection module.

2. The protection system of claim 1, further comprising a fuse connected to the plurality of battery cells, the fuse configured to be controlled by the first protection signal output by the output of the first protection module.

3. The protection system of claim 2, wherein the first protection module is configured to monitor a state of the first group of battery cells and the second protection module is configured to monitor a state of the second group of battery cells, wherein if an abnormal condition in the second group of battery cells is detected, the second protection module outputs the second protection signal to the first monitoring terminal of the first protection module and the output terminal of the first protection module outputs the first protection signal to blow the fuse.

4. A protection system according to any one of claims 1 to 3 wherein the abnormal condition comprises an overvoltage condition.

5. The protection system of claim 1, wherein the detection module of the first protection module comprises:

the monitoring circuit is connected with the monitoring ends of the first protection module and is configured to monitor the states of a plurality of battery voltages, and if one of the battery voltages is greater than a reference voltage, the monitoring circuit generates an indication signal;

a delay circuit connected to the monitoring circuit and configured to start timing in response to the indication signal and to generate the first protection signal after the delay time; and

a fast detection circuit connected to the delay circuit, wherein the fast detection circuit changes the delay time from the first time interval to the second time interval if the fast detection circuit receives the second protection signal from the output terminal of the second protection module at the switching terminal of the first protection module.

6. The protection system of claim 5, wherein the plurality of battery voltages includes a cell voltage of the first group of battery cells connected with the first protection module and a cell voltage of the second group of battery cells connected with the second protection module, and wherein the signal on the first monitor terminal of the first protection module is controlled by a state of the cell voltage of the second group of battery cells.

7. The protection system of claim 5 or 6, wherein the fast detection circuit comprises a comparator configured to compare a voltage difference between the switching terminal and the first monitoring terminal of the first protection module with a threshold voltage and to generate a resultant signal to control the delay circuit in accordance with the comparison.

8. A battery pack, the battery pack comprising:

a first group of battery cells;

a second group of battery cells connected to the first group of battery cells;

a first protection module connected with the first group of battery units and used for generating a first protection signal for protecting the first group of battery units; and

a second protection module connected to the second group of battery cells, generating a second protection signal for protecting the second group of battery cells,

wherein each of the first and second protection modules comprises:

the monitoring terminals are used for monitoring the states of a corresponding group of battery units in the first group of battery units and the second group of battery units;

an output terminal for outputting a protection signal of the protection module when an abnormal condition is detected in the corresponding group of battery cells;

the switching terminal is used for receiving a switching signal; and

a detection module connected to the plurality of monitoring terminals, the output terminal, and the switch terminal, and configured to: switching from a normal operation mode to a rapid test mode in response to the switching signal, and generating a protection signal of the protection module after a delay time when an abnormal condition is detected in the corresponding group of battery cells, wherein the detection module sets the delay time to a first time interval if the abnormal condition is detected in the normal operation mode, and sets the delay time to a second time interval less than the first time interval if the abnormal condition is detected in the rapid test mode,

the switching end and the first monitoring end of the first protection module are connected with the second protection module and used for receiving signals from the output end of the second protection module.

9. The battery pack of claim 8, wherein the battery pack further comprises a fuse connected to the first and second sets of battery cells, the fuse configured to be controlled by the first protection signal output by the output of the first protection module.

10. The battery pack of claim 9, wherein the first protection module is configured to monitor a state of the first group of cells and the second protection module is configured to monitor a state of the second group of cells, wherein if an abnormal condition in the second group of cells is detected, the second protection module outputs the second protection signal to the first monitoring terminal of the first protection module and the output terminal of the first protection module outputs the first protection signal to blow the fuse.

11. The battery pack of any of claims 8-10, wherein the abnormal condition comprises an overvoltage condition.

12. The battery pack of claim 8, wherein the detection module of the first protection module comprises:

13. The battery pack of claim 12, wherein the plurality of battery voltages comprises a cell voltage of the first group of battery cells and a cell voltage of the second group of battery cells, and wherein the signal on the first monitor terminal of the first protection module is controlled by a state of the cell voltage of the second group of battery cells.

14. A battery pack, as claimed in claim 12 or 13, wherein the fast detection circuit comprises a comparator configured to compare a voltage difference between the switching terminal and the first monitoring terminal of the first protection module with a threshold voltage and to generate a resultant signal to control the delay circuit in dependence on the comparison.

15. A protection method of protecting a battery pack including at least a first group of battery cells and a second group of battery cells, the protection method comprising:

monitoring the state of the first group of battery units through a plurality of monitoring ends of a first protection module;

if the abnormal condition is detected in the first group of battery units, outputting a first protection signal through a first output end of the first protection module after delay time;

receiving a switching signal at a switching end of the first protection module;

controlling the first protection module to switch from a normal working mode to a fast testing mode in response to the switching signal;

setting the delay time to a first time interval if the abnormal condition is detected in the normal operating mode;

setting the delay time to a second time interval less than the first time interval if the abnormal condition is detected in the fast test mode;

monitoring, by a second protection module, a state of the second group of battery cells; and

outputting a second protection signal through a second output terminal of the second protection module if an abnormal condition is detected in the second group of battery cells,

the switching end of the first protection module and the first monitoring end of the first protection module receive the second protection signal from the second output end of the second protection module.

16. The protection method according to claim 15, wherein the protection method further comprises:

controlling fuses connected with the first group of battery cells and the second group of battery cells by the first protection signal.

17. The protection method according to claim 15 or 16, wherein the protection method further comprises:

monitoring, by a monitoring circuit in the first protection module, a state of a plurality of battery voltages;

if the battery voltage in the plurality of battery voltages is greater than the reference voltage, generating an indication signal;

starting timing in response to the indication signal;

generating the first protection signal by a delay circuit in the first protection module after the delay time; and

changing the delay time from the first time interval to the second time interval if the second protection signal is received at the switching end of the first protection module.

18. The protection method according to claim 17, wherein the protection method further comprises:

comparing a voltage difference between the switching terminal and the first monitoring terminal of the first protection module with a threshold voltage; and

controlling the delay circuit according to the result of the comparison.